The parse activity is used in any workflow where files are uploaded. It is the main activity for recognizing a files format and extracting meta-data in XMP format. It has a number of options related to the type of file being processed. The output of the parse activity is an XMP file containing data and metadata for the parsed file.
See also
http://tech.teradp.com/tech/html/gn4/docs/VSdoc/frlrfTeraDPGN4WorkflowActivityParseClassTopic.html